Vibration-type gyro sensors are widely used as an angular velocity sensor for consumer use. The vibration-type gyro sensor detects an angular velocity by causing a vibrator to vibrate at a predetermined frequency and detecting a Coriolis force generated in the vibrator using a piezoelectric device and the like. The gyro sensor is mounted on electronic apparatuses such as a video camera, a virtual reality apparatus, a car navigation system, and a wearable apparatus and is used as sensors for detecting hand movements, operations, directions, postures, and the like.
For example, Patent Literature 1 discloses an angular velocity sensor that includes an annular frame and a plurality of pendulum portions having one ends thereof connected to the frame and is capable of detecting angular velocities about 3 axes orthogonal to one another on the basis of a deformation amount of the frame and plurality of vibrators vibrating at a predetermined frequency.
Typically, in the vibration-type gyro sensor, a drive electrode for causing the vibrator to vibrate using an inverse piezoelectric effect and a detection electrode for detecting a deformation of the vibrator using a piezoelectric effect are each provided on a front surface of the vibrator. Wirings respectively connected to the drive electrode and the detection electrode are formed on the front surface of the vibrator.
For example, Patent Literature 2 discloses an angular velocity sensor device in which a plurality of wiring patterns are formed on a front surface of a twist extension portion that connects a fixed portion and a drive vibration body. In a wiring layout disclosed in Patent Literature 2, a plurality of detection wiring patterns are arranged between a pair of drive wiring patterns. Therefore, noises are apt to enter the detection wiring patterns from the drive wiring patterns, thus leading to a fear of inducing angular velocity detection accuracy. This problem may become more prominent as the device becomes smaller.
As a countermeasure for noises, for example, Patent Literature 3 discloses an angular velocity sensor in which a ratio of amplitudes of two drive signals is set to become an inverse ratio with respect to a ratio of parasitic capacitances caused between two drive electrodes and detection electrodes. Accordingly, noise components generated due to capacitance coupling between the first and second drive electrodes and detection electrodes are offset, and detection accuracy of angular velocity sensor signals is assumed to be improved. However, the angular velocity sensor disclosed in Patent Literature 3 presupposes a single angular velocity detection axis and thus cannot cope with a case where there are a plurality of detection signals like the angular velocity sensors disclosed in Patent Literatures 1 and 2.